Electrical switch



May 12, 1931. G. o. WILMS ET AL ELECTRICAL SWITCH Filed Oct. 17, 1927 2Sheets-Sheet l y 1931- G. o. WILMS ET AL ELECTRICAL SWITCH Filed Oct.17, 1927 2 Sheets-Sheet 2 Maud M. 12, 1931 UNITED STATES PATENT OFFICEGUSTAV O. AND FREDERICK I. LOOCK, OF MILWAUKEE, WISCONSIN, ABSIGNORS,

BY IESNE ASSIGNMENTS, TO THE'RELIANCE COMPANY, OI WILMINGTON, DELA-WARE, A CORPORATION OF DELAWARE ELECTRICAL swrrcn Application filedOctober 17, 1927. Serial No. 228,665.

This invention relates to certain new and useful improvements in meansfor minimiz ing destructive arcs occurring between switch contacts atthe time of the rupture of a circuit therebetween, and has as an objectthe provision of an improved hood enclosing the contacts.

Many types of devices have been designed to overcome destructive arcingforces, such as the well-known arc chute consisting of plates disposedon each side of the contacts and the provision of magnetic blowout meansof which Letters Patent Number 967,280, issued Harold E. White, August1516, 1910, is an example.

The types of arc minimizing means heretofore employed have onlypartially offset the effects of the arc and have also been open to theobjection of bulkiness-and the consequent inability to house the samewithin a casin made to fit the switch pr0per, and this 1nvention has asanother object the provision of an improved means for limiting andreducing the formation of destructive arcs at the contacts of switcheswhich is of reduced size to require no increase in the size of thecasing enclosing the switch mechanism and which will efficiently preventthe destruction of the contacts by the formation of an arc therebetweenupon separation under load.

Another object of this invention resides in the provision of an improveddevice of the character described which consists of a hood entirelyenclosing the contacts and which is open only at the point of entranceof the contacts.

A further object of this invention resides in the provision of animproved device of the character described which is in the form of anelongated hood member having spaced transverse walls or partitionsdividing the same into sections or compartments to adapt the hood memberfor use with a plurality of pairs of contacts.

Astill further object of this invention resides in the provision of animproved hood member of the character described which is formed of arefractory material such as porcelain and coated to prevent the chemicalreaction occurring upon the separation of With the above and otherobjects in view which will appear as the description proceeds, ourinvention resides in the novel construction, combination and arrangementof parts substantially as hereinafter described and more particularlydefined by the appended claims, it being understood that such changes inthe precise embodiment of the herein disclosed invention may be made ascome Within the scope of the claims.

In the accompanying drawings, We have illustrated two complete examplesof the physical embodiment of our invention constructed according to thebest modes we have so far devised for the practical application of theprinciples thereof, and in which:

Figure 1 is a front view, of a switch mechanism equipped with ourinvention, a part of the enclosing casing being broken away and theswitch mechanism proper being partly in front elevation and partly insection;

Figure 2 is a view, taken transversely through the up er end portion ofthe switch mechanism on the plane of the line 2-2 of Figure 1, theswitch mechanism proper being partly in side elevation and partly insection;

Figure 3 is a perspective view of the improved arc hood detached fromthe switch mechanism;

Figure 4 is a view, partly in section and partly in side elevation, of aswitch mechanism apart from its enclosin housing and equipped with aslightly modified form of arc hood;

. Figure 5 is a front elevational view of a switch mechanism equip edwith the type of-arc hood illustrated in Figure 4, and

Figure 6 is a pers ective view of one of the arc hoods of the mo 'fiedconstruction.

Referrin now more particularly to the accompanying drawings in which hkenumerals designate like parts throughout the several views, 5 designatesa box or housing hinged or otherwise removably mounted cover 6 in whichis fixed a base or panel 7 of slate or other insulating material fromwhich the switch mechanism is sup orted.

The switch mechanism may be c any design or construction," the oneillustrated in the drawings consisting of a plurality of spacedlaterally extended standards or arms 8 fixed to the upper end of thepanel, as at 9, and having stationar contacts 10 on their outer endsadapted to e engaged by moveable contactors 11 having a suitable springconnection 12 with a cross arm 13 of insulating material. The cross arm.is fixed to the outer free end portion 14 of an armature pivotallymounted, as at 15, to cooperate with an actuating magnet 16 supportedfrom the panel 7.

The standards of arms 8 are preferably of channel shape in cross sectionand the inner-most arms have upwardly and, outwardly inclined supports17 riveted or otherwise secured thereto, as at 18, which provide meansfor mounting a hood member 1 19 forming the arc reducing or limitingmeans now about to bedescribed.

The hood 19 is preferably of refractory material such as porcelain orthe like and is in one piece and of the shape best shown in Fi ures 2and 5 having conver in front and rear walls 20 and 21, respectlve yconnected b a curved wall 22 and end walls 23, interme iate spacedpartitions 24 dividing the hood into a plurality of compartments 25 inwhich the pairs of cooperating contacts extend. The wall 21 terminatesshort of wall 20 and the rear portion of the partitions 24 is stepped,as at 26, to accommodate the coil 16 and its mounting frame. The wall 21has enlargements 27 on its rear surface which are a ertured, as at 28,to receive the supports 1 and thus mount the hood as best shown inFigure 2 with the contacts 10 and 11 entirely disposed within theirrespective compartments which are open to the atmosphere only at theside of entrance of the contacts.

If the arc hoods are formed of porcelain, a coating of enamel or othersuitable material is applied to prevent the chemical reaction which isset up when an arc is enclosed in porcelain.

In the form of my invention illustrated in Figures 4, 5 and 6,individual arc hoods 29 are provided. In this instance, the supports 30for the stationary contacts 10, which are secured at one end of thepanel 7, have their medial portions bent substantially V-shaped, as at31, and. from one of the sides of the V-shaped portions studs .32 extendupwardly and outwardly, the studs being secured to the medial portionsof the supports by riveting or any other suitable means. Each of, thearc hoods 29 consists of spaced sides 33 connected by a curved mousewall 34 and a straight wall 35, which continues tangentially therefrom,the distance between the ends of the walls 34 and 35 being open to theatmosphere and providing the point of entrance of the movable contacts.The wall 35 has a longitudinal aperture 36 to receive the stud 32 andthe lower portion of the wall 34 is'cut away, as at 37, to receive theadjacent portions 31 of the supporting arm upon which the hood rests.Thus it Wlll be seen that each arc hood 29 is readily removably suported by its arm 30 and substantially'enc oses the adjacent pair ofcontacts 10 and 11 tolimit the are formed upon opening of the switch.Forming the arc hoods separately, asillustrated in this form of myinvention, allows ready individual inspection of the contacts, as it isonly necessary to lift the desired hood to' immediately expose thecontacts to view.

It has been found by experiment that the smaller the area within thecompartment surrounding the contacts, the more cflicient the suppressionof the arc tending to form upon the separation of the contacts. It hasalso been found that the cross-sectional shape of the compartment asshown is especially eflicient, althou h its shape may be varied, and thesides of t e compartment are in close relation to the contacts and thearc spreads on the walls and is cooled, the hood dissipatin the heat byradiation.

From the foregoing description taken in connection with the accompanyingdrawings, it will be readily apparent to those skilled in the art towhich an invention of the character described appertains that I haveprovided an arc hood which is simple in construction, readily removablyen ageable over the contacts, and which effectively limits the formationof an are at the opening of the contacts materially reducing theduration of time through which the are holds on, thus greatly increasingthe capacity of the switch with which it is used.

What we claim as our invention is:

1. A device for limiting destructive arcing between the contacts of anelectric switch, com'prisinga hood formed of insulating material closedon all sides except its bottom to form a confining chamber substantiallyencasing the contacts, and means readily removably mounting the hood.

2. The combination with an electric switch having a stationary contact,a movable con? tact and means mounting the stationary contact,of an arcsuppressing hood closed on i all sides except its bottom to form aconfining chamber-encasing the contacts, and cooperating means carriedby the hood and the stationary" contact mounting means for 3. Incombination with an electric switch having a stationary contact, amovable contact and means for mounting the stationary contact, of a hoodadapted to substantially encase the contacts on all sides except thebottom, and means removably mounting the hood from the stationarycontact mounting means and including a member carried by the lastmentioned means.

4. In combination with an electric switch having a stationary contact, amovable contact and means mounting the stationary contact, of a hoodmember closed on all sides except its bottom and having a recess in onewall, a'nd'a supporting member extended from the stationary contactsupporting means seated'in said recess to support the hood member withthe contacts positioned therein, said supporting member being disposedin a plane parallel with the direction of movementnecessary to lift thehood from the contacts.

5. In combination with an electric switch having a plurality of pairs ofstationary and movable contacts, of a hood member of insulating materialand having separated compartments formed therein into which the pairs ofcontacts extend, said compartments being substantially closed on allsides except their bottoms to closely confine the contacts and limitdestructive arcing thereat,

and means readily removably mounting the hood member.

6. The combination with an electric switch including a stationarycontact and a movable contact, of a hood member substantially enclosingthe contacts on all sides save the bottom, and means mounting the hoodmember whereby it is free to be moved to expose the contacts.

7. The combination with an electric switch including a stationarycontact, a movable contact and means mounting the stationary contact, ofa hood member substantially enclosing the contacts onall sides save thebottom, a supporting member carried by the stationary contact mountingmeans, and means connectin the hood member with said supporting mem erwhereby the hood memher is free to be moved to expose the contacts.

8. In combination with an electric switch having separable contacts,means for limiting destructive arcing between the contacts as they areseparated, comprisin a hood formed of insu ating material and open tothe atmosphere only at its bottom, and means mounting the hood in aposition whereby the 7 contacts enter the hood from the bottom and aresubstantially encased thereby on all sides save the bottom.

9. In combination with an electric switch having a plurality of' pairs'of separable contacts, means for limiting destructive arcing betweenthe airs of contacts as they are separated and confining said arc's' totheir respective pairs of contacts, comprising a member having a numberof pockets corresponding to the number of pairs of contacts, and meansmounting said member so that a pair of contacts is received in eachpocket, the pockets being substantially closed exce t at their bottomortions throu h whic the contacts enter t e same where y the pocketsform relatively confined enclosures for the contacts.

10. In combination with an electric switch having a plurality of pairsof side by side separable contacts, and inverted substantially troughlike hood member of insulating material, side wise spaced partitions inthe hood member dividing the sameinto side by side pockets, and meansreadily detachably mountin said hood member over the contacts with apair of contacts disposed in each pocket with the partitions betweenadjacent pairs of contacts, said pockets being sub stantially closedexcept at their bottoms so that the contacts operate within relatively12. In combination with an electric switch having a plurality of pairsof side by side separable contacts, a. unit having wall members closelyconfining each pair of contacts on all sides except the bottom so thatthe pairs of contacts operate within relatively confined enclosures.

In testimony whereof we have hereunto affixed our signatures.

GUSTAV O. WILMS.

FREDERICK F. LOOCK.

